#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int main ()
{
	int money = 0;
	int total = 0;
	int empty = 0;
	scanf("%d",&money);
	total = money;
	empty = money;
	while(empty >= 2)
	{
	    total += empty/2;
		empty = empty/2 + empty%2;
	}
	printf("%d\n",total);
    return 0;
}